1. Field of the Invention
This invention relates to a plastic valve, or a valve made of a synthetic resin. Specifically, it pertains to a plastic valve of the type in which a body and a flanged body cap are connected by screwing with a cap nut.
2. Description of the Prior Art
In FIG. 1, which illustrates a conventional plastic valve of the type in which a body and a flanged body cap are coupled by a cap nut, the reference numeral 1 represents a body; 2, a handle; 3, a ball; 4, a union; 5, a body cap; 5a, an annular seat of the body cap 5; 6, a cap nut; 6a, an annular holding bottom of the cap nut 6; 7, a flange; and 8, a welded or screwed part of the flange 7. In coupling the body cap 5 to the body 1, the body cap 5 is inserted into the cap nut 6 and then the cap nut 6 is screwed to the body 1. As a result, the holding bottom 6a of the cap nut 6 causes the seat 5a of the body cap 5 to be press-bonded to the union 4 thereby achieving intimate coupling between the body and the body cap.
In such a conventional valve, it is necessary, before securing the flange 7 to the body cap 5, to put the cap nut 6 around the body cap 5 from the flange-securing side of the body cap 5 and then to weld or screw the flange 7 to the body cap 5. For this reason, the flange and the body cap cannot be built as an integral unit, with the result that the strength of the flange-securing portion of the body cap is reduced and cracks tend to form at this portion. Moreover, the number of valve assembling steps naturally increases.
The present invention has been made in order to remove the aforesaid defects of conventional valves. It is therefore an object of this invention to provide a plastic valve which can be built by a lesser number of assembling steps than in the case of conventional valves of this type, and can be disassembled more easily than the conventional valves.
Another object of this invention is to provide a plastic valve which has higher strength than the conventional valves of this type because its flange portion and body cap can be molded as an integral unit.